The present invention regards a subsea cooling unit.
Coolers in general are of course well known in the art, for example as radiators in automobiles and refrigerator systems. One example of a representative cooler is shown in GB 2145806 which shows a stack of serpentine coils used in a cooler for a refrigerator. Another example of a cooling system is described in WO 2009/046566 which shows a cooling unit being assembled from bends and straight pieces of stainless steel. There are also known subsea coolers, on example is WO2008/004885, which describes a lightweight underwater cooling assembly.
It is well known that a compressor's function is in part dependent upon the temperature of the medium that shall be compressed, and it has been shown that cooling the medium increases the efficiency of the compressor. In a subsea environment it is especially important because of the remoteness and difficult access to a subsea installation which creates the need for efficient cooling as this leads to savings in the compressor. Add to this the remoteness which creates its own challenges for reliability and fault-free running. However, cooling a hydrocarbon well stream may create other problems since there usually is entrenched water in the well stream and cooling enables water to be separated out as free water and this may lead to hydrate formation. It is therefore important that a subsea cooling unit is well adapted to the specific use and amount and composition of the medium to be cooled.
There is therefore a need for a cooler which is easy assembled and adaptable for the specific use subsea, to achieve the necessary cooling.
A cooling unit as defined in the attached claims provides a solution to this need.